The ultimate purpose of the program project grant is to elucidate the control mechanisms involved in epidermal proliferation and differentiation and the application of this information to the efficacious treatment of psoriasis. The roles of the cyclic nucleotides (cyclic AMP, cyclic GMP, cyclic CMP, and cyclic TMP) and the components of the prostaglandin cascade (arachidonic acid, HETE, PGE2, PGF2 alpha) in these control mechanisms are the focal points of the research at this time. Compounds which have been effective in controlling proliferation and/or differentiation in model systems by altering the levels of the compounds listed above, will be evaluated in double-blind clinical trials as to their effectiveness in treating psoriasis with minimal side effects.